Pinpoint Test G: U012D, U042E
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
- Refer to Wiring Diagrams Charging System
for schematic and connector information.
Normal Operation and Fault Conditions
The charging system supplies voltage to the battery and the vehicle electrical system through the battery B+ cable. The PCM monitors the generator output through a LIN communication circuit shared with the automatic grill shutters (AGS). The PCM uses this LIN circuit to communicate the desired voltage setpoint to the generator internal voltage regulator. The generator also uses this to communicate the generator load and error conditions to the PCM.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM U012D:00 Lost Communication With Generator "A" Control Module: No Sub Type Information Sets if the PCM does not detect communication through the LIN circuit. This can be a result of an open or short in the LIN circuit. This DTC also sets if the generator B+ circuit is open. PCM U042E:00 Invalid Data Received From Generator "A" Control Module: No Sub Type Information Sets when the PCM receives invalid data from the generator. Possible Sources
- Battery monitoring sensor
- Generator
- PCM
- Active Grille Shutter
- Wiring, terminals or connectors
Visual Inspection and Pre-checks
- Inspect high current BJB for loose, damaged or corroded connections.
- Inspect the BJB fuse 201 (300A).
- Inspect the BJB fuse 25 (10A).
- Inspect the FEAD belt.
- Inspect the battery monitoring sensor.
- NOTE: Make sure battery voltage is greater than 12.2 volts prior to and during this pinpoint test.
- NOTE: Do not have a battery charger attached during vehicle testing.
- G1 CHECK VEHICLE FOR PRESENCE OF GRILLE SHUTTERS
- While looking through the grille opening, inspect the vehicle for the presence of grille shutters. REFER to: Active Grille Shutter Actuator .
Is the vehicle equipped with grille shutters?
Yes GO to G2 No GO to G3 - G2 RETRIEVE PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) WITH GRILLE SHUTTER ACTUATOR DISCONNECTED
- Ignition OFF.
- Disconnect Grille Shutter Actuator C1765 and C1766.
- Ignition ON.
- Using a diagnostic scan tool, perform the PCM self-test.
Is DTC U012D or U042E present?
Yes GO to G3 No INSTALL new grille shutter actuator. REFER to: Active Grille Shutter Actuator . - G3 COMPARE THE GENERATOR B+ CIRCUIT TO BATTERY VOLTAGE
- Measure: for (3.3L engine)
Positive Lead Measurement / Action Negative Lead C1251A-1 Ground
- Measure: for (5.0L) engine
Positive Lead Measurement / Action Negative Lead C1104A-1 Ground
Is the voltage within 0.5 volt of the recorded battery voltage?
Yes GO to G4 No TIGHTEN or INSTALL a new generator B+ nut as needed. REFER to: Generator - 3.3L Duratec-V6 . REFER to: Generator - 5.0L 32V Ti-VCT . VERIFY high current BJB fuse 201 (300A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short. - Measure: for (3.3L engine)
- G4 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect Generator (3.3L engine) C102A.
- Disconnect Generator (5.0L engine) C1104A.
- Disconnect PCM (3.3L engine) C1551B.
- Disconnect PCM (5.0L engine) C1381B.
- Ignition ON.
- Measure: for (3.3L engine)
Positive Lead Measurement / Action Negative Lead C1251A-1 Ground
- Measure: for (5.0L) engine
Positive Lead Measurement / Action Negative Lead C1104A-1 Ground
Is any voltage present?
Yes REPAIR the circuit. No GO to G5 - G5 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- For 3.3L engine, Measure:
Positive Lead Measurement / Action Negative Lead C102A-1 Ground
- For 5.0L engine, Measure:
Positive Lead Measurement / Action Negative Lead C1104A-1 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to G6 No REPAIR the circuit. - G6 CHECK THE GENERATOR LIN (LOCAL INTERCONNECT NETWORK) CIRCUIT FOR AN OPEN
- For 3.3L engine, Measure:
Positive Lead Measurement / Action Negative Lead C102A-1 C1551B-49 C102A-1 Upper active grille shutter actuatorC1766-2 C102A-1 Lower active grille shutter actuatorC1765-2
- For 5.0L engine, Measure:
Positive Lead Measurement / Action Negative Lead C1104A-1 C1381B-49 C1104A-1 Upper active grille shutter actuatorC1766-2 C1104A-1 Lower active grille shutter actuatorC1765-2
Is the resistance less than 3 ohms?
Yes INSTALL a new generator. REFER to: Generator - 3.3L Duratec-V6 . REFER to: Generator - 5.0L 32V Ti-VCT . REPEAT the PCM self-test. If DTC U012D is retrieved again, GO to G7 No REPAIR the affected circuit. - For 3.3L engine, Measure:
- G7 CHECK FOR CORRECT PCM (POWERTRAIN CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect all PCM connectors.
- Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary
- Reconnect the PCM connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, Refer to PCM GUIDED ROUTINE TESTING
Internet Explorer version 11 or greater is required to perform this Pinpoint Test.No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.